With the diffusion of rapid processing in recent years, a huge amount of color photographic light-sensitive materials for printing (hereinafter referred to as simply light-sensitive materials or color papers) are processed rapidly. Rapid processing is a very strong demand in a color photography field, and a great many improvements therefor have been made and new rapid systems have been developed every few years. For realizing the rapid processing, it is necessary to shorten independently each step of the processing, such as a step of color developing, a step of bleach-fixing, a step of washing and a step of drying. As a method of realizing the rapid processing, International Patent Publication No. WO87/04534, for example, discloses a method of processing rapidly using a color photographic light-sensitive material employing a high silver chloride emulsion, and it shows that the use of a high silver chloride photographic emulsion is preferable from the viewpoint of rapid processing. However, it is known that when the rate of containing silver chloride is enhanced, silver chloride photographic emulsion has a disadvantage that its sensitivity is generally low, although the developing speed therefor can be improved remarkably. There have been made various attempts to make a silver halide photographic emulsion having high rate of containing silver chloride to be highly sensitive to overcome the disadvantage mentioned above.
Recently, the number of stores having a minilab of a rapid processing type installed is increased year after year. There has been a growth of business enjoying an advantage of a minilab of a rapid processing type, including an introduction of a minilab for the service to make a customer to have a print without waiting in a pleasure resort, or an introduction of a minilab in a store other than a professional photographic store. Accordingly, an amount of color papers used is increased year by year. With regard to color papers, there are demanded those with stable performance wherein sensitivity and gradation are always constant without any dispersion so that persons other than a photographic specialist can make a print simply under the same condition. In the photographic business field, various studies have been made so that stable color papers can be supplied. It is generally known that storage life of a silver halide emulsion is poor showing that its photographic sensitivity is lowered and fog increases rapidly. For example, Japanese Patent O.P.I. Publication Nos. 323645/1992 and 222523/1994 disclose a technology for stabilizing sensitivity and fog fluctuation in an emulsion solution. The technology, however, is for preventing performance fluctuations with time in a solution for a period of time covering emulsion dissolution through coating, and it has a disadvantage that dispersed performance of an emulsion existing before dissolution of the emulsion remains as it is undesirably. Under the circumstances mentioned above, the inventors of the invention studied, in many ways, technologies for stabilizing performance of an emulsion in the course of manufacture of the emulsion.
U.S. Pat. Nos. 2,463,794, 2,489,341, 2,565,418, 2,614,928, 2,618,556, 2,996,287, 3,241,969, 3,498,454, 4,990,439, and RD. Vol. 102, October, 1972, Item 10208 disclose compounds containing 2-naphthylsulfonic acid. These technologies represent those added as a coagulation/sedimentation agent, in the course of a desalting process for silver halide. However, as a result of various studies of these technologies, the inventors have found that these technologies tend to vary in terms of performance and thereby to cause fluctuation in the performance though they function as a coagulation/sedimentation agent.
Japanese Patent O.P.I. Publication Nos. 181240/1993 and 281649/1993 disclose a technology to add sulfonic acid compounds. However, the sulfonic acid compound of the technology is not added in the course of chemical ripening but is added in a step of preparation for coating, and its object is not an improvement of performance fluctuation of an emulsion.